Renfro was discovered by his roommates not breathing Tuesday morning. His friends called 911, but paramedics declared Renfro dead at the scene at about 9 a.m., People.com reported.
He was 25.
The magazine said the actor, who has a history of drug abuse, had been drinking Monday night.
Although Renfro had been convicted of several drug offenses and struggled with addiction for years, TMZ.com cited sources who said he had been working hard to stay clean in recent months.
"As critical and prescient as you become in this town, all I did was cry when I heard the news," Renfro's former defense attorney Blair Berk told People.com. "I feel in some respects like we all failed."
Coroner's office Lt. Cheryl MacWillie told the magazine the autopsy will be conducted Thursday, but it usually takes several weeks to get toxicology test results.